Rebel minis has Zombie Dogs that would work fine for post apocalyptic and maybe even as normal dogs since the Zombie aspect is not too noticeable. Splintered light has some dogs with a handler in their historical range as well as a pack of wolves in their miscellaneous section (along with some other cool critters like Terror Birds). You could contact David McBride of Splintered Light to see if you could purchase some dogs separately. Splintered Light also has a lizard that looks like some type of dog in the lizardmen pack. It would make a cool alien or post apocalyptic dog since it has three eyes.

splintered lights wolves can easily be painted up as larger german shepherds or you can get the wardogs from the medieval irish set and just put the handler in the spares box. very nice irish wolfhounds.

I used the Guard dog from the Laserburn line available from " link " . In my option, a lot of figures in this Laserbburn line are useful for a post apocalyptic / Fallout game. The thugs, police, civilian and some some of the power armor figures are real useful.

The Russians used dogs as anti tank weapons in WWII, albeit not terribly successfully & they're used in mine detection work. Wiki for a useful summary link & a bit more on mine dogs here link Battlefront make them in 15mm IIRC.

Are dogs even used in modern warfare for anything other than guard duty and tracking?

Not really. The only dogs I've seen in military service are German Shepherds for guard work and a nice beagle that had a good nose. The beagle was great for shipboard searches, since he was small enough to lower through a hatch.

Keep in mind that dogs are great for finding the insurgent trying to hide from you, too. I've seen pictures of Military Working Dogs on patrol in Iraq. The real problem is a lack of body armor for the pups.